On July 1, 2025, Mayor Bruce Harrell signed Seattle City Council Bill 121000 which bans the use of algorithmic software designed to propose rent rates for residential landlords.[1] This new law is codified in Chapter 7.34 of the Seattle Municipal Code and could have broad impacts for owners and property management companies using software which proposes rental rates based on publicly and/or privately available market data.
A. How this New Law Impacts Landlords
CB 121000 prohibits a landlord from “contracting with or otherwise exchanging anything of value in return for the coordinating services of a service provider.” It also prohibits service providers from providing “coordinating services to two or more landlords.” “Coordinate” and “coordinating” means a service provider’s:
(1) collecting historical, anticipated, or contemporary prices, price changes, supply levels, occupancy rates, or lease or rental contract termination and renewal dates of residential dwelling units from two or more landlords, from private databases, or from public databases; and (2) analyzing or processing the information described in (1) through the use of a system or software that utilizes an algorithmic or other automated process to provide recommendations regarding rental prices, lease renewal terms, or occupancy levels to more than one landlord. “Coordinate” and “coordinating” do not include publishing rental price estimates that:
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- Are solely based on publicly available information;
- Are equally available to all members of the public; and
- Do not require a contract or agreement to obtain.
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“Service provider” is defined to mean “any person that performs a coordinating function.”
There is likely to be litigation over the scope and application of this new law. In fact, a similar law to passed in Berkeley, California was challenged earlier this year, in part, because the law failed to provide fair notice of “what conduct it prohibits,” which interested parties in the industry (such as RealPage) allege violates the Due Process Clause of the Fourteenth Amendment. The Berkeley law has been suspended amid litigation brought by RealPage to challenge its enforceability. Whether a court would rule similarly regarding Seattle’s new law remains to be seen.
The new law does not apply to prices set for short-term rentals like AirBnBs or hotels and does not extend to basic record-keeping software. Software and publications that estimate prices based solely on public information and do not require contracts or licenses are likewise not banned.
Violations of this CB 121000 are punishable via a new civil penalty of up to $7,500.00 per violation. CB 121000 further creates a new private right of action for tenants harmed by these violations, which would allow tenants to sue for damages of up to $7,500.00 per violation.
B. Key Takeaways
Landlords in Seattle should check any rent-setting practices and ensure they are not using software that could expose them to liability. They should also stay vigilant for any additional guidance from the City. CB 121000 directs the Seattle Department of Construction & Inspections (SDCI) to perform landlord outreach to help with compliance.
If you have any further questions regarding how the new law affects you, please reach out to one of the landlord-tenant attorneys at Montgomery Purdue.
[1] CB 121000